Small Engines (Lawn Mowers, etc.): John Deere stx 38, mouse damage, john deere stx 38

Question
I have a John Deere stx 38 with a kohler engine.  I know absolutly nothing about small engine repair, so I've been taken for a ride more than once.  I had the starter replaced, new battery, and something in the engine that helps it start, it might have a magnet on it or something.  Anyway the thing is dead as a door nail.  I try to switch it on and nothing.  I did have a problem with mice and the last time I had it open, some of the wires were chewed a little.  I'm not even sure how to get to the main bolt off the top to look inside.  I'm asking because I could probably do it myself, if I knew what to look for.  I've already spent too much on this thing.  I'm a teacher and I don't have a lot of money for things like this.  It's probably best to pay someone but it is worth me at least asking.  

Answer
The visible mouse damage is just the tip of the iceberg.
The main mouse damage will be under the fan shroud. Mice damage is extremely common.
What level of teaching do you do. If you teach at a high school do a little networking. If your school offers small engine repair this would be a great class project. An electronics class might also enjoy the challenge.
If you can't find help through school take the tractor to a dealer, not a small engine shop, not the guy on the corner who fixes mowers on the side, take it to a dealer.
What ever you do don't get rid of the mower. An STX is an excellent tractor that will last you many years.
Get it repaired by the dealer and then buy a product called "Mouse-Out" they will have it at the Deere dealer.
If you can't figure out how to take the nut off the top to look in side you're probably in over your head.
Another option is to pay the dealer to diagnose only. It should cost under 50.00 and replace the parts yourself. Sometimes just doing the diagnostics will solve the problem.